Car-brake



(No Model.)

E- P- ROBERTS.

GAR BRAKE.

UNITE STATES PATENT OFFICE.

EDVARD F. ROBERTS, OF ROCHESTER, NE\V YORK, ASSIGNOR TO THE ROBERTS MANUFACTURING COMPANY, OF OHIO. l

CAR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 433,039, dated July 29, 1890.

Application filed April 2, 1890. Serial No. 346,278. (No model.)

y To all whom it may concern:

Be it known that I, EDWARD F. ROBERTS, a citizen of Great Britain, residing at. Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Carlrakesg and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention consists of the improved form of brake-bar and auxiliary brace therefor, hereinafter to be more particularlydescribed and claimed.

In the drawings, Figure l shows the brakebar with its attachments and the brace in plan view and partial section. Fig. cis a View of the bra-heshoe and cross-section on the line Y Y of Fig. l, and Fig. 3 is a crosssection of Fig. l on the line X X.

Throughout the drawings like referenceletters refer to like parts.

It is a necessity in the brakegear to be used with power^brakessuch as air-brakes in railroad-cars-that the brake-bar shall have but a slight degree ot deflection when the full power of the brakes is applied. The usual wooden brake-bar cannot be made strong enough to secure the rigidity required without making it cumbersome, and yet on account of usage and of the many good points of the wooden brake-bar it is not desirable to altogether discard the saine and substitute therefor a metal one. In order to produce a brake-bar in which this requirement ot' rigidity shall be met, and at the same time the various advantages of the wooden brake-bar be maintained, I have designed the herewith illustrated apparatus, in which- B is a wooden brake-bar of the usual shape and dimensions, upon which the brake-slices S S are mounted by means of the straps R R', pins s s', and bolts or keys r 1", as shown in Figs. 1 and 2. In the back of the brake bar is cut a longitudinal scarf A, into which the metal brace A is introduced, as shown in Figs. l and 3. The said brace bears on the brake-bar only at its ends, as clearly shown in Fig. 1, this being assured by the placing of any suitable bearing-plate beneath each end of said brace. The preferred construction, however, is that clearly illustrated in Fig. 3, in which the strap Q conforms to the contourof the cross-section of the brake-bar on the line X X, and has its ends fastened by the screws q c] or other equivalent means. In this way the bar is bound together, and the strain is distributed over the whole of the same.

The chain operating the brakes may of course be attached directly to the brace A, or it may be attached to the strap T, surrounding the brake-bar and bearing on the brace A, as shown in Fig. 1. In the usual form of construction, however, the said strap T would have pivoted to it a lever L, which would be operated by the rod and chain connectionsin the manner well known in this art.

The operation of my invention is evident from the above description. Then the strain is applied by means of the lever L to the brake-bar, instead of being concentrated at Vthe central point of the bar, it is distributed equally upon the points under the straps Q Q', and thereby transmitted to the brake-shoes without subjecting the brakebar to the bendingfstrain which would arise in case the entire power were applied at the center of the brake-bar in the usual manner. The extent to which the strain may be diminished depends, of course, upon the distance of the ends or bearing-points of the auxiliary brace from the center of the brake-bar. As these points are more or less remote from the center of the brake-bar, the strain is correspondingly decreased or increased. The proportion in which this strain is reduced can of course be determined by the usual formula in such cases. Thus, for instance, if the entire distance between the brake-shoes be represented by II II ll II, as indicated by the arrows in Fig. l, and the distance of each of the bearing-straps Q Q from the center is one-fourth the entire length of the bar, or H, and if the strain upon the strap T is represented bythe force I), then itis evident, of course, that the strain upon the straps R R will be equal to one-half the force I), and by the familiar formula, if the entire strain P were applied at the center of the brake-bar, the bending moment at that point would be represented by the product of 2-H into .2f-P. If by the TOO use of my invention the force P is equally distributed at the points Q Q', this Strain at each point will be -P, and by the formula again the bending moment of the brake-bar at every point between the points Q Q will be equal to the product of H into Tff-P, or only one-halt the maximum strain in the first case. By removing the points Q Q still farther from the center of the brake-bar this strain may be still'further reduced.

The advantages of my invention are that a brake-bar of the requisite strength is produced without destroyingr the lightness ot' the wooden bar or materially departing from the present Shape. W

My improvement can be applied to any brake-bar now in use, and new brake-bars c0n structed on the principle of my invention can be applied to the regular brake-gear now used.

Having therefore described my invention, what I claim as new, and desire to protect by Letters Patent, is

1. The combination of the brakebar, the auxiliary brace, the ends of which bear against the brake-bar at points more or less remote from the center thereof, and the 0perating-lever connected to or bearing upon said brace, substantially as described.

2. The combination of the brake-bar, the auxiliary brace embedded in said brake-bar, the ends of which brace bear against the brake-bar at points more or less remote from the center thereof, the strap which surrounds the center of the bar and bears upon the brace, and the operating-lever connected to said strap, substantially as described.

In testimony whereof I afx my signature in presence of two witnesses.

EDWARD E. ROBERTS.

NVitneSSes:

W. MARTIN JONES, WILLIAM E. DAVIS. 

